The present invention relates to compositions that are useful as catalyst activators for olefin polymerizations. More particularly the present invention relates to such compositions that are particularly adapted for use in the coordination polymerization of unsaturated compounds having improved activation efficiency and performance. Such compositions are particularly advantageous for use in a polymerization process wherein catalyst, catalyst activator, and at least one polymerizable monomer are combined under polymerization conditions to form a polymeric product.
It is previously known in the art to activate Ziegler-Natta polymerization catalysts, particularly such catalysts comprising Group 3-10 metal complexes containing delocalized xcfx80-bonded ligand groups, by the use of an activator. Generally in the absence of such an activator compound, also referred to as a cocatalyst, little or no polymerization activity is observed.
A class of suitable activators are Lewis acids, especially alumoxanes, which are generally believed to be oligomeric or polymeric alkylaluminoxy compounds, including cyclic oligomers. Examples of alumoxanes (also known as aluminoxanes) include methylalumoxane (MAO) made by hydrolysis of trimethylaluminum as well as modified methylalumoxane (MMAO), wherein a portion of the trimethylaluminum in the foregoing hydrolysis is replaced by a higher trialkylaluminum compound such as triisobutylaluminum. MMAO advantageously is more soluble in aliphatic solvents than is MAO.
Generally alumoxanes contain on average about 1.5 alkyl groups per aluminum atom, and are prepared by reaction of trialkylaluminum compounds or mixtures of compounds with water (Reddy et al, Prog. Poly. Sci., 1995, 20, 309-367). The resulting product is in fact a mixture of various substituted aluminum compounds including especially, trialkylaluminum compounds (resulting from incomplete reaction of the trialkylaluminum starting reagent or decomposition of the alumoxane). The amount of such free trialkylaluminum compound in the mixture generally varies from 1 to 50 percent by weight of the total product.
Although effective in forming an active olefin polymerization catalyst when combined with a variety of Group 3-10 metal complexes, especially Group 4 metal complexes, generally a large excess of alumoxane compared to metal complex, such as, molar ratios from 100:1 to 10,000:1, is required in order to produce adequate rates of polymerization. Unfortunately, the use of such large excesses of cocatalyst is expensive and also results in polymer having an elevated residual aluminum content as well as lower molecular weight. This former factor may adversely affect polymer properties, especially clarity and dielectric constant, whereas the latter issue relates to poor polymer performance.
Other types of monomeric aryloxyaluminum and arylamidoaluminum complexes have been found to be useful in metallocene catalyst activator packages, particularly as water and oxygenate scavengers. Examples include diisobutyl-2,6-di-t-butyl-4-methylphenoxyaluminum (DIBAL-BOT) as described in WO 97/27228 and Japanese kokai, 09-17629, or diisobutylhexamethyldisilylazayl aluminum (DIBAL-NS) as described by Rosen et al in WO 98/03558. Typically in such formulations, the Lewis acid, especially tris(pentafluorophanyl)borane, is first contacted with a metal complex to prepare the catalytically activated derivative. Thereafter, this derivative is generally not subject to ligand transfer with the aluminum compound.
A different type of activator compound is a Bronsted acid salt capable of transferring a proton to form a cationic derivative or other catalytically active derivative of such Group 3-10 metal complex, cationic charge transferring compounds, or cationic oxidizing activators, referred to collectively hereinafter as cationic activators. Preferred cationic activators are ammonium, sulfonium, phosphonium, oxonium, ferrocenium, silver, lead, carbonium or silylium compounds containing a cation/anion pair that is capable of rendering the Group 3-10 metal complex catalytically active. Preferred anions associated with this cation comprise fluorinated arylborate anions, more preferably, the tetrakis(pentafluorophenyl)borate anion. Additional suitable anions include sterically shielded, bridged diboron anions. Examples of such cationic activators are disclosed in U.S. Pat. Nos. 5,198,401, 5,132,380, 5,470,927, 5,153,157, 5,350,723, 5,189,192, 5,626,087 and in 5,447,895.
Further suitable activators for activating metal complexes for olefin polymerization include neutral Lewis acids such as tris(perfluorophenyl)borane and tris-(perfluorobiphenyl)borane. The former composition has been previously disclosed for the above stated end use in U.S. Pat. No. 5,721,185, and elsewhere, whereas the latter composition is disclosed in Marks, et al, J. Am. Chem. Soc. 1996, 118, 12451-12452. Additional teachings of the foregoing activators may be found in Chen, et al, J. Am. Chem. Soc. 1997, 119, 2582-2583, Jia et al, Organometallics, 1997, 16, 842-857, and Coles et al, J. Am. Chem. Soc. 1997, 119, 8126-8126.
Tris(perfluorophenyl)aluminum is a strong Lewis acid as well. It has recently been prepared from the exchange of tris(perfluorophenyl)borane with trialkylaluminum, which gives a trialkylborane and tris-perfluorophenylaluminum, as described by Biagini et al U.S. Pat. No. 5,602,269. However, it generally performs poorly by itself as a catalyst activator compared with tris(perfluorophenyl)borane when used in an equimolar ratio with a metal complex. Similarly, It has further been demonstrated that active catalysts resulting from the use of an aluminate anion based upon tris-(perfluorophenyl)aluminum for the activation of ansa-metallocenes and biscyclopentadienyl derivatives of zirconium(IV) are generally of lower activity than those formed by the corresponding borane (Ewen, Stud. in Surf. Sci. Catal. 1994, 89, 405-410). A possible explanation for the poor performance of tris(perfluorophenyl)aluminum as an activator for metallocenes involving a back exchange reaction of a perfluorophenyl group has been proposed by Bochmann et al (ACS Dallas Meeting, March 1998, Abs. number INOR 264, subsequently published, Organometallics, 1998, 17, 5908-5912).
In light of these apparent deficiencies, it would be desirable to provide novel compounds having improved efficiency and operability as activators of metal complexes for olefin polymerizations.
According to the present invention there is now provided a compound corresponding to the formula: AlArfQ1Q2, or a dimer, adduct, or mixture thereof; where:
Arf is a fluorinated aromatic hydrocarbyl moiety of from 6 to 30 carbon atoms;
Q1 is Arf or a C1-20 hydrocarbyl group, optionally substituted with one or more cyclohydrocarbyl, hydrocarbyloxy, hydrocarbylsiloxy, hydrocarbylsilylamino, hydrocarbylsilyl, silylhydrocarbyl, di(hydrocarbylsilyl)amino, hydrocarbylamino, di(hydrocarbyl)amino, di(hydrocarbyl)phosphino, or hydrocarbylsulfido groups having from 1 to 20 atoms other than hydrogen, or, further optionally, such substituents may be covalently linked with each other to form one or more fused rings or ring systems; and
Q2 is an aryloxy, arylsulfide or di(hydrocarbyl)amido group, optionally substituted with one or more hydrocarbyl, cyclohydrocarbyl, hydrocarbyloxy, hydrocarbylsiloxy, hydrocarbylsilylamino, hydrocarbylsilyl, silylhydrocarbyl, di(hydrocarbylsilyl)amino, hydrocarbylamino, di(hydrocarbyl)amino, di(hydrocarbyl)phosphino, or hydrocarbylsulfido groups having from 1 to 20 atoms other than hydrogen, or, further optionally such substituents may be covalently linked with each other to form one or more fused rings or ring systems, said Q2 having from 3 to 20 atoms other than hydrogen.
The subject invention further provides a method for preparing the foregoing compound comprising contacting under ligand exchange reaction conditions a trifluoroarylaluminum or trifluoroarylboron compound of the formula Arf3Me1,
wherein Arf is as previously defined, and
Me1 is aluminum or boron,
with a Group 13 organometallic compound of the formula: Q32Me2Q2, wherein
Q2 is as previously defined;
Q3 is independently each occurrence C1-4 alkyl; and
Me2 is a Group 13 metal, with the proviso that if Me1 is boron, then Me2 is aluminum.
In a particular embodiment of the foregoing method for preparing the compounds, a stoichiometric excess of the Group 13 organometallic compound of the formula: Q32Me2Q2 is employed in the ligand exchange reaction. The resulting reaction mixture accordingly does not include significant quantities of residual trifluoroarylaluminum or trifluoroarylboron compound.
The subject invention further provides a catalyst composition for polymerization of olefins comprising a Group 3-10 metal complex and an activator comprising the above described compound or composition, the molar ratio of metal complex to activator in the catalyst composition being from 0.1:1 to 3:1.
The subject invention further provides a process for the polymerization of one or more addition polymerizable monomers comprising contacting one or more addition polymerizable monomers under addition polymerization conditions with the catalyst composition as described above.
These and other embodiments are more fully described in the following detailed description.
All references herein to elements belonging to a certain Group refer to the Periodic Table of the Elements published and copyrighted by CRC Press, Inc., 1995. Also any reference to the Group or Groups shall be to the Group or Groups as reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups. The full teachings of any patent, patent application, provisional application, or publication referred to herein are hereby incorporated by reference.
Preferred compositions according to the present invention are those wherein Ar is a perfluoroaryl group, more preferably a perfluorophenyl group, Q1 is C3-6 alkyl containing at least one secondary or tertiary carbon center, more preferably isopropyl or isobutyl, and Q2 is aryloxy or dialkylamido of up to 10 carbons, more preferably 2,6-di-(t-butyl)phenoxy, 2,6-di-(t-butyl)-4-methylphenoxy, N,N-bis(trimethylsilyl)amido, or N,N-dimethylamido. Most preferred compounds are monomers, rather than dimers or adducts.
In another preferred embodiment, the foregoing compounds are prochiral and optically inactive, however four coordinate derivatives thereof are chiral.
A most preferred aluminum compound formed according to the invention is isobutyl(perfluorophenyl)-2-methyl-4,6-di-(t-butyl)phenoxyaluminum or isobutyl(perfluorophenyl)-4,6-di-(t-butyl)phenoxyaluminum.
In a preferred process for making the compounds of the invention the exchange reaction is conducted in an aliphatic, cycloaliphatic or aromatic hydrocarbon liquid or mixture thereof under anhydrous conditions. Preferably, the Group 13 organometallic compound is an aluminum compound and is provided in a stoichiometric excess with respect to the trifluoroaryl aluminum or trifluoroaryl boron compound, more preferably at a molar ratio from 1:1 to 20:1, most preferably from 1:1 to 10:1. Preferred are the use of solutions of the foregoing reactants in concentrations of fluoroaryl compound and Group 13 compound from 0.005 to 2M, preferably from 0.02 to 1.5 M, and most preferably from 0.05 to 1.2 M. Generally, the Group 13 organometallic compound readily transfers one Q3 group. However, the rate of transfer of a second Q3 group is kinetically disfavored, thereby allowing for the recovery of the desired product in high yield and efficiency.
The rate of ligand exchange can be enhanced by heating the reaction mixture or by removing any alkyl exchange byproducts in the reaction mixture, especially any trialkylborane byproducts. A preferred temperature range for the exchange reaction is from 0 to 50xc2x0 C., more preferably from 15 to 35xc2x0 C. Suitable techniques for removing alkyl exchange byproducts from the reaction mixture include degassing optionally at reduced pressures, distillation, solvent exchange, solvent extraction, extraction with a volatile agent, contacting with a zeolite or molecular sieve, and combinations of the foregoing techniques, all of which are conducted according to conventional procedures. Purity of the resulting product may be determined by analysis of the reaction mixture. Desirably the content of trialkylboron compound in the compounds of the invention is less than 1 percent by weight, preferably less than 0.1 percent by weight. Removal of volatile by-products will assist in shifting the equilibrium concentration of desired end products. Generally, reaction times from 10 minutes to 6 hours, preferably 15 minutes to 1 hour are used to ensure formation of the desired ligand exchange products.
In as much as the present compounds are desirably prepared by an exchange reaction as previously described, it is to be understood that the resulting product mixture may include species in addition to those of the formula, AlArfQ1Q2. Additional components may include starting reactants as well as alternative exchange products. It is to be understood that the compounds of the invention may be prepared and used in the form of such a mixture of compounds. More particularly, alternative exchange products and starting reactants that may be found in such a mixture include compounds corresponding to the formula: [Me1Q13] where:
Q1 is Arf or a C1-20 hydrocarbyl group, optionally substituted with one or more cyclohydrocarbyl, hydrocarbyloxy, hydrocarbylsiloxy, hydrocarbylsilylamino, hydrocarbylsilyl, silylhydrocarbyl, di(hydrocarbylsilyl)amino, hydrocarbylamino, di(hydrocarbyl)amino, di(hydrocarbyl)phosphino, or hydrocarbylsulfido groups having from 1 to 20 atoms other than hydrogen, or, further optionally, such substituents may be covalently linked with each other to form one or more fused rings or ring systems;
Arf is a fluorinated aromatic hydrocarbyl moiety of from 6 to 30 carbon atoms; and
Me1 is boron or aluminum, especially aluminum.
The exchange process is more particularly illustrated by reference to the following particular embodiment. (Isobutyl)(perfluorophenyl)(2-methyl-4,6-di-t-butylphenoxy)aluminum, which has been found to be an effective and useful cocatalyst for use in olefin polymerizations in combination with a group 4 metal complex, may be prepared by reacting tris(perfluorophenyl)borane (FAB) with diisobutyl-2,6-di-t-butyl-4-methylphenoxyaluminum (DIBAL-BOT) in a suitable diluent, preferably a hydrocarbon liquid. Preferably, the DIBAL-BOT is provided in stoichiometric excess with respect to the FAB. Further preferably, the two reagents are combined in solutions having concentrations of at least 0.005 M, preferably at least 0.05 M, more preferably at least 0.02 M; and, for reasons of solubility, typically no more than 2 M, preferably, no more than 1.5 M, and most preferably no more than 1.2 M. The use of excess Di-BAL-BOT insures the production of tri-coordinate aluminum species and likewise efficiently distributes all of the costly perfluoroaryl groups to aluminum, the co-product being mainly triisobutylboron, as illustrated in the following reaction scheme: 
The rate of exchange reaction can be conveniently monitored by 19F and 1H NMR spectroscopy to ensure complete reaction.
In an alternate preferred embodiment of the invention, the activator isobutylperfluorophenyl-2-methyl-4,6-di-t-butylphenoxyaluminum, is prepared by reacting tris-(perfluorophenyl)aluminum (FAAL, which typically exists as a stoichiometric toluene solvate) with DiBAL-BOT in a hydrocarbon or aromatic solvent to produce the isobutylperfluorophenyl-2-methyl-4,6-di-t-butylphenoxyaluminum via an intermediate species, bis-perfluorophenylisobutylaluminum. This alternate embodiment of the invention is illustrated by the following reaction scheme: 
In this process, lower ratios of FAAL:DIBALBOT (1:1-1:2) form a highly active formulation, consisting of essentially two active aluminum components, bis-perfluorophenylisobutyl-aluminum and (perfluorophenyl)(isobutyl)(2-methyl-4,6-di-t-butylphenoxy)aluminum. It has now been determined that the partial exchange product, bis-perfluorophenylisobutylaluminum, is a highly active cocatalyst for use with group 4 metal complexes in an olefin polymerization. The use of higher ratios of DIBAL-BOT to FAAL (5-10:1) favors extinction of bisperfluorophenylisobutylaluminum and increases the amount of isobutylperfluorophenyl-2-methyl-4,6-di-t-butylphenoxyaluminum in the mixture. These ratios are not intended to limit the nature of the invention and may provide a suitable means for tailoring the efficiency of broad classes of metal complexes which may require a combination of these activators.
The present composition provides a highly active co-catalyst for use in activation of metal complexes, especially Group 4 metallocenes for the polymerization of olefins. In such use it is desirably employed as a dilute concentration in a hydrocarbon liquid, especially an aliphatic hydrocarbon liquid for use as a homogeneous catalyst, especially for solution polymerizations. Additionally, the composition may be deposited on an inert support, especially a particulated metal oxide or polymer, in combination with the metal complex to be activated according to known techniques for producing supported olefin polymerization catalysts, and thereafter used for gas phase or slurry polymerizations.
The present compounds and compositions provide highly active co-catalysts for use in activation of metal complexes, especially Group 4 metallocenes for the polymerization of olefins. In such use they are desirably employed as a dilute solution in a hydrocarbon liquid, especially an aliphatic hydrocarbon liquid for use as a homogeneous catalyst, especially for solution polymerizations. Additionally, the compound, or composition may be deposited on an inert support, especially a particulated metal oxide or polymer, in combination with the metal complex to be activated according to known techniques for producing supported olefin polymerization catalysts, and thereafter used for gas phase or slurry polymerizations.
When in use as a catalyst activator, the molar ratio of metal complex to activator composition is preferably from 0.1:1 to 3:1, more preferably from 0.2:1 to 2:1, most preferably from 0.25:1 to 1:1, based on the metal contents of each component. In most polymerization reactions the molar ratio of metal complex: polymerizable compound employed is from 10xe2x88x9212:1 to 10xe2x88x921:1, more preferably from 10xe2x88x9212:1 to 10xe2x88x925:1.
The support for the activator component may be any inert, particulate material, but most suitably is a metal oxide or mixture of metal oxides, preferably alumina, silica, an aluminosilicate or clay material. Suitable volume average particle sizes of the support are from 1 to 1000 xcexcM, preferably from 10 to 100 xcexcM. Most desired supports are calcined silica, which may be treated prior to use to reduce surface hydroxyl groups thereon, by reaction with a silane, a trialkylaluminum, or similar reactive compound. Any suitable means for incorporating the perfluoroaryl)aluminum co-catalyst mixture onto the surface of a support may be used, including dispersing the co-catalyst in a liquid and contacting the same with the support by slurrying, impregnation, spraying, or coating and thereafter removing the liquid, or by combining the cocatalyst and a support material in dry or paste form and intimately contacting the mixture, thereafter forming a dried, particulated product.
Suitable metal complexes for use in combination with the foregoing cocatalysts include any complex of a metal of Groups 3-10 of the Periodic table of the Elements capable of being activated to polymerize addition polymerizable compounds, especially olefins by the present activators. Examples include Group 10 diimine derivatives corresponding to the formula: 
wherein 
M* is Ni(II) or Pd(II);
Xxe2x80x2 is halo, hydrocarbyl, or hydrocarbyloxy;
Ar* is an aryl group, especially 2,6-diisopropylphenyl or aniline group; and
CTxe2x80x94CT is 1,2-ethanediyl, 2,3-butanediyl, or form a fused ring system wherein the two T groups together are a 1,8-naphthanediyl group.
Similar complexes to the foregoing are disclosed by M. Brookhart, et al., in J. Am. Chem. Soc., 118, 267-268 (1996) and J. Am. Chem. Soc., 117, 6414-6415 (1995), as being suitable for forming active polymerization catalysts especially for polymerization of xcex1-olefins, either alone or in combination with polar comonomers such as vinyl chloride, alkyl acrylates and alkyl methacrylates.
Additional complexes include derivatives of Group 3, 4, or Lanthanide metals containing from 1 to 3 xcfx80-bonded anionic or neutral ligand groups, which may be cyclic or non-cyclic delocalized xcfx80-bonded anionic ligand groups. Exemplary of such xcfx80-bonded anionic ligand groups are conjugated or nonconjugated, cyclic or non-cyclic dienyl groups, allyl groups, boratabenzene groups, phosphoyl groups and arene groups. By the term xe2x80x9cxcfx80-bondedxe2x80x9d is meant that the ligand group is bonded to the transition metal by a sharing of electrons from a delocalized xcfx80-bond.
Each atom in the delocalized 7u-bonded group may independently be substituted with a radical selected from the group consisting of hydrogen, halogen, hydrocarbyl, halohydrocarbyl, hydrocarbyloxy, hydrocarbylsulfide, dihydrocarbylamino, and hydrocarbyl-substituted metalloid radicals wherein the metalloid is selected from Group 14 of the Periodic Table of the Elements, and such hydrocarbyl-, halohydrocarbyl-, hydrocarbyloxy-, hydrocarbylsulfide-, dihydrocarbylamino- or hydrocarbyl-substituted metalloid-radicals that are further substituted with a Group 15 or 16 hetero atom containing moiety. Included within the term xe2x80x9chydrocarbylxe2x80x9d are C1-20 straight, branched and cyclic alkyl radicals, C6-20 aromatic radicals, C7-20 alkyl-substituted aromatic radicals, and C7-20 aryl-substituted alkyl radicals. In addition two or more such radicals may together form a fused ring system, including partially or fully hydrogenated fused ring systems, or they may form a metallocycle with the metal. Suitable hydrocarbyl-substituted organometalloid radicals include mono-, di- and tri-substituted organometalloid radicals of Group 14 elements wherein each of the hydrocarbyl groups contains from 1 to 20 carbon atoms. Examples of suitable hydrocarbyl-substituted organometalloid radicals include trimethylsilyl, triethylsilyl, ethyidimethylsilyl, methyldiethylsilyl, triphenylgermyl, and trimethylgermyl groups. Examples of Group 15 or 16 hetero atom containing moieties include amine, phosphine, ether or thioether moieties or divalent derivatives thereof, for example amide, phosphide, ether or thioether groups bonded to the transition metal or Lanthanide metal, and bonded to the hydrocarbyl group or to the hydrocarbyl-substituted metalloid containing group.
Examples of suitable anionic, delocalized xcfx80-bonded groups include cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl, tetrahydrofluorenyl, octahydrofluorenyl, pentadienyl, cyclohexadienyl, dihydroanthracenyl, hexahydroanthracenyl, decahydroanthracenyl groups, and boratabenzene groups, as well as C1-10 hydrocarbyl-substituted, C1-10 hydrocarbyloxy-substituted, di(C1-10 hydrocarbyl)amino-substituted, or tri(C1-10 hydrocarbyl)silyl-substituted derivatives thereof. Preferred anionic delocalized xcfx80-bonded groups are cyclopentadienyl, pentamethylcyclopentadienyl, tetramethylcyclopentadienyl, tetramethylsilylcyclopentadienyl, indenyl, 2,3-dimethylindenyl, fluorenyl, 2-methylindenyl, 2-methyl-4-phenylindenyl, tetrahydrofluorenyl, octahydrofluorenyl, and tetrahydroindenyl.
The boratabenzenes are anionic ligands which are boron containing analogues to benzene. They are previously known in the art having been described by G. Herberich, et al., in Organometallics, 1995, 14, 1, 471-480. Preferred boratabenzenes correspond to the formula: 
wherein Rxe2x80x3 is selected from the group consisting of hydrocarbyl, silyl, or germyl, said Rxe2x80x3 having up to 20 non-hydrogen atoms. In complexes involving divalent derivatives of such delocalized xcfx80-bonded groups one atom thereof is bonded by means of a covalent bond or a covalently bonded divalent group to another atom of the complex thereby forming a bridged system.
Suitable metal complexes for use in the catalysts of the present invention may be derivatives of any transition metal including Lanthanides, but preferably of Group 3, 4, or Lanthanide metals which are in the +2, +3, or +4 formal oxidation state meeting the previously mentioned requirements. Preferred compounds include metal complexes (metallocenes) containing from 1 to 3 xcfx80-bonded anionic ligand groups, which may be cyclic or noncyclic delocalized xcfx80-bonded anionic ligand groups. Exemplary of such xcfx80-bonded anionic ligand groups are conjugated or nonconjugated, cyclic or non-cyclic dienyl groups, allyl groups, and arene groups. By the term xe2x80x9cxcfx80-bondedxe2x80x9d is meant that the ligand group is bonded to the transition metal by means of delocalized electrons present in a xcfx80 bond.
Examples of suitable anionic, delocalized xcfx80-bonded groups include cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl, tetrahydrofluorenyl, octahydrofluorenyl, pentadienyl, cyclohexadienyl, dihydroanthracenyl, hexahydroanthracenyl, and decahydroanthracenyl groups, as well as C1-10 hydrocarbyl-substituted derivatives thereof. Preferred anionic delocalized xcfx80-bonded groups are cyclopentadienyl, pentamethylcyclopentadienyl, tetramethylcyclopentadienyl, indenyl, 2,3-dimethylindenyl, fluorenyl, 2-methylindenyl and 2-methyl-4-phenylindenyl.
More preferred are metal complexes corresponding to the formula:
LlMXmXxe2x80x2nXxe2x80x3p, or a dimer thereof
wherein:
L is an anionic, delocalized, xcfx80-bonded group that is bound to M, containing up to 50 atoms not counting hydrogen, optionally two L groups may be joined together through one or more substituents thereby forming a bridged structure, and further optionally one L may be bound to X through one or more substituents of L;
M is a metal of Group 4 of the Periodic Table of the Elements in the +2, +3 or +4 formal oxidation state;
X is an optional, divalent substituent of up to 50 non-hydrogen atoms that together with L forms a metallocycle with M;
Xxe2x80x2 is an optional neutral Lewis base having up to 20 non-hydrogen atoms;
Xxe2x80x3 each occurrence is a monovalent, anionic moiety having up to 40 non-hydrogen atoms, optionally, two Xxe2x80x3 groups may be covalently bound together forming a divalent dianionic moiety having both valences bound to M, or form a neutral, conjugated or nonconjugated diene that is xcfx80-bonded to M (whereupon M is in the +2 oxidation state), or further optionally one or more Xxe2x80x3 and one or more Xxe2x80x2 groups may be bonded together thereby forming a moiety that is both covalently bound to M and coordinated thereto by means of Lewis base functionality;
l is 1 or 2;
m is 0 or 1;
n is a number from 0 to 3;
p is an integer from 0 to 3; and
the sum, l+m+p, is equal to the formal oxidation state of M.
Such preferred complexes include those containing either one or two L groups. The latter complexes include those containing a bridging group linking the two L groups. Preferred bridging groups are those corresponding to the formula (ER*2)x wherein E is silicon or carbon, R* independently each occurrence is hydrogen or a group selected from silyl, hydrocarbyl, hydrocarbyloxy and combinations thereof, said R* having up to 30 carbon or silicon atoms, and x is 1 to 8. Preferably, R* independently each occurrence is methyl, benzyl, tert-butyl or phenyl.
Examples of the foregoing bis(L) containing complexes are compounds corresponding to the formula: 
wherein:
M is titanium, zirconium or hafnium, preferably zirconium or hafnium, in the +2 or +4 formal oxidation state;
R3 in each occurrence independently is selected from the group consisting of hydrogen, hydrocarbyl, dihydrocarbylamino, hydrocarbyleneamino, silyl, germyl, cyano, halo and combinations thereof, said R3 having up to 20 atoms not counting hydrogen, or adjacent R3 groups together form a divalent derivative thereby forming a fused ring system, and
Xxe2x80x3 independently each occurrence is an anionic ligand group of up to 40 atoms not counting hydrogen, or two Xxe2x80x3 groups together form a divalent anionic ligand group of up to 40 atoms not counting hydrogen or together are a conjugated diene having from 4 to 30 atoms not counting hydrogen forming a xcfx80-complex with M, whereupon M is in the +2 formal oxidation state, and
R*, E and x are as previously defined.
The foregoing metal complexes are especially suited for the preparation of polymers having stereoregular molecular structure. In such capacity it is preferred that the complex possess C2 symmetry or possess a chiral, stereorigid structure. Examples of the first type are compounds possessing different delocalized xcfx80-bonded systems, such as one cyclopentadienyl group and one fluorenyl group. Similar systems based on Ti(IV) or Zr(IV) were disclosed for preparation of syndiotactic olefin polymers in Ewen, et al., J. Am. Chem. Soc. 110, 6255-6256 (1980). Examples of chiral structures include bis-indenyl complexes. Similar systems based on Ti(IV) or Zr(IV) were disclosed for preparation of isotactic olefin polymers in Wild et al., J. Organomet. Chem, 232, 233-47, (1982).
Exemplary bridged ligands containing two xcfx80-bonded groups are: (dimethylsilyl-bis-cyclopentadienyl), (dimethylsilyl-bis-methylcyclopentadienyl), (dimethylsilyl-bis-ethylcyclopentadienyl, (dimethylsilyl-bis-t-butylcyclopentadienyl), (dimethylsilyl-bis-tetramethylcyclopentadienyl), (dimethylsilyl-bis-indenyl), (dimethylsilyl-bis-tetrahydroindenyl), (dimethylsilyl-bis-fluorenyl), (dimethylsilyl-bis-tetrahydrofluorenyl), (dimethylsilyl-bis-2-methyl-4-phenylindenyl), (dimethylsilyl-bis-2-methylindenyl), (dimethylsilyl-cyclopentadienyl-fluorenyl), (1,1,2,2-tetramethyl-1,2-disilyl-bis-cyclopentadienyl), (1,2-bis(cyclopentadienyl)ethane, and (isopropylidene-cyclopentadienyl-fluorenyl).
Preferred Xxe2x80x3 groups are selected from hydride, hydrocarbyl, silyl, germyl, halohydrocarbyl, halosilyl, silylhydrocarbyl and aminohydrocarbyl groups, or two Xxe2x80x3 groups together form a divalent derivative of a conjugated diene or else together they form a neutral, xcfx80-bonded, conjugated diene. Most preferred Xxe2x80x3 groups are C1-20 hydrocarbyl groups.
A further class of metal complexes utilized in the present invention correspond to the formula:
LlMXmXxe2x80x2nXxe2x80x3p, or a dimer thereof
wherein:
L is an anionic, delocalized, xcfx80-bonded group that is bound to M, containing up to 50 atoms not counting hydrogen;
M is a metal of Group 4 of the Periodic Table of the Elements in the +2, +3 or +4 formal oxidation state;
X is a divalent substituent of up to 50 non-hydrogen atoms that together with L forms a metallocycle with M;
Xxe2x80x2 is an optional neutral Lewis base ligand having up to 20 non-hydrogen atoms;
Xxe2x80x3 each occurrence is a monovalent, anionic moiety having up to 20 non-hydrogen atoms, optionally two Xxe2x80x3 groups together may form a divalent anionic moiety having both valences bound to M or a neutral C5-30 conjugated diene, and further optionally Xxe2x80x2 and Xxe2x80x3 may be bonded together thereby forming a moiety that is both covalently bound to M and coordinated thereto by means of Lewis base functionality;
l is 1 or 2;
m is 1;
n is a number from 0 to 3;
p is an integer from 1 to 2; and
the sum, l+m+p, is equal to the formal oxidation state of M.
Preferred divalent X substituents preferably include groups containing up to 30 atoms not counting hydrogen and comprising at least one atom that is oxygen, sulfur, boron or a member of Group 14 of the Periodic Table of the Elements directly attached to the delocalized xcfx80-bonded group, and a different atom, selected from the group consisting of nitrogen, phosphorus, oxygen or sulfur that is covalently bonded to M.
A preferred class of such Group 4 metal coordination complexes used according to the present invention correspond to the formula: 
wherein:
M is titanium or zirconium in the +2 or +4 formal oxidation state;
R3 in each occurrence independently is selected from the group consisting of hydrogen, hydrocarbyl, silyl, germyl, cyano, halo and combinations thereof, said R3 having up to 20 non-hydrogen atoms, or adjacent R3 groups together form a divalent derivative (that is, a hydrocarbadiyl, siladiyl or germadiyl group) thereby forming a fused ring system,
each Xxe2x80x3 is a halo, hydrocarbyl, hydrocarbyloxy or silyl group, said group having up to 20 atoms not counting hydrogen, or two Xxe2x80x3 groups together form a C5-30 conjugated diene;
Y is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NR*xe2x80x94, xe2x80x94PR*xe2x80x94; and
Z is SiR*2, CR*2, SiR*2SiR*2, CR*2CR*2, CR*xe2x95x90CR*, CR*2SiR*2, or GeR*2, wherein: R* is as previously defined.
Illustrative Group 4 metal complexes that may be employed in the practice of the present invention include:
cyclopentadienyltitaniumtrimethyl,
cyclopentadienyltitaniumtriethyl,
cyclopentadienyltitaniumtriisopropyl,
cyclopentadienyltitaniumtriphenyl,
cyclopentadienyltitaniumtribenzyl,
cyclopentadienyltitanium-2,4-pentadienyl, cyclopentadienyltitaniumdimethylmethoxide,
cyclopentadienyltitaniumdimethylchloride, pentamethylcyclopentadienyltitaniumtrimethyl,
indenyltitaniumtrimethyl,
indenyltitaniumtriethyl,
indenyltitaniumtripropyl,
indenyltitaniumtriphenyl,
tetrahydroindenyltitaniumtribenzyl,
pentamethylcyclopentadienyltitaniumtriisopropyl,
pentamethylcyclopentadienyltitaniumtribenzyl,
pentamethylcyclopentadienyltitaniumdimethylmethoxide,
(xcex75-2,4-dimethyl-1,3-pentadienyl)titaniumtrimethyl,
octahydrofluorenyltitaniumtrimethyl,
tetrahydroindenyltitaniumtrimethyl,
tetrahydrofluorenyltitaniumtrimethyl,
(1,1-dimethyl-2,3,4,9,10-xcex7-1,4,5,6,7,8-hexahydronaphthalenyl)titaniumtrimethyl,
(1,1,2,3-tetramethyl-2,3,4,9,10-xcex7-1,4,5,6,7,8-hexahydronaphthalenyl)titaniumtrimethyl,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium dimethyl,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)-1,2-ethanediyltitanium dimethyl,
(tert-butylamido)(hexamethyl-xcex75-indenyl)dimethylsilanetitanium dimethyl,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilane titanium (III) 2-(dimethylamino)benzyl;
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium (III) allyl,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium (II) 1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(2-methylindenyl)dimethylsilanetitanium (II) 1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(2-methylindenyl)dimethylsilanetitanium (IV) 1,3-butadiene,
(tert-butylamido)(2,3-dimethylindenyl)dimethylsilanetitanium (II) 1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(2,3-dimethylindenyl)dimethylsilanetitanium (IV) 1,3-butadiene,
(tert-butylamido)(2,3-dimethylindenyl)dimethylsilanetitanium (II)1,3-pentadiene,
(tert-butylamido)(2-methylindenyl)dimethylsilanetitanium (II) 1,3-pentadiene,
(tert-butylamido) (2-methylindenyl)dimethylsilanetitanium (IV) dimethyl,
(tert-butylamido) (2-methyl-4-phenylindenyl)dimethylsilanetitanium (II) 1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium (IV) 1,3-butadiene,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium (II ) 1,4-dibenzyl-1,3-butadiene,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium (II) 2,4-hexadiene,
(tert-butylamido)(tetramethyl-xcex75-cyclopentadienyl)dimethylsilanetitanium (II) 3-methyl 1,3-pentadiene,
(tert-butylamido)(2,4-dimethyl-1,3-pentadien-2-yl)dimethylsilanetitaniumdimethyl,
(tert-butylamido)(1,1-dimethyl-2,3,4,9,10-xcex7-1,4,5,6,7,8-hexahydronaphthalen-4-yl)dimethylsilanetitaniumdimethyl,
(tert-butylamido)(1,1,2,3-tetramethyl-2,3,4,9,10-xcex7-1,4,5,6,7,8-hexahydronaphthalen-4-yl)dimethylsilanetitaniumdimethyl,
(tert-butylamido)(tetramethylcyclopentadienyl)dimethylsilanetitanium 1,3-pentadiene,
(tert-butylamido)(3-(N-pyrrolidinyl)inden-1-yl)dimethylsilanetitanium 1,3-pentadiene,
(tert-butylamido)(2-methyl-s-indacen-1-yl)dimethylsilanetitanium 1,3-pentadiene, and (tert-butylamido)(3,4-cyclopenta(/)phenanthren-2-yl)dimethylsilanetitanium 1,4-diphenyl-1,3-butadiene.
Bis(L) containing complexes including bridged complexes suitable for use in the present invention include:
biscyclopentadienylzirconiumdimethyl,
biscyclopentadienylzirconiumdiethyl,
biscyclopentadienylzirconiumdiisopropyl,
biscyclopentadienylzirconiumdiphenyl,
biscyclopentadienylzirconium dibenzyl,
biscyclopentadienylzirconium-2,4-pentadienyl,
biscyclopentadienylzirconiummethylmethoxide,
bispentamethylcyclopentadienylzirconiumdimethyl,
bisindenylzirconiumdimethyl,
indenylfluorenylzirconiumdiethyl,
bisindenylzirconiummethyl(2-(dimethylamino)benzyl),
bisindenylzirconium methyltrimethylsilyl,
bistetrahydroindenylzirconium methyltrimethylsilyl,
bispentamethylcyclopentadienylzirconiumdiisopropyl,
bispentamethylcyclopentadienylzirconiumdibenzyl,
bispentamethylcyclopentadienylzirconiummethylmethoxide,
(dimethylsilyl-bis-cyclopentadienyl)zirconiumdimethyl,
(dimethylsilyl-bis-pentamethylcyclopentadienyl)zirconium-2,4-pentadienyl,
(methylene-bis-pentamethylcyclopentadienyl)zirconium(III) 2-(dimethylamino)benzyl,
(dimethylsilyl-bis-2-methylindenyl)zirconiumdimethyl,
(dimethylsilyl-bis-2-methyl-4-phenylindenyl)zirconiumdimethyl,
(dimethylsilyl-bis-2-methylindenyl)zirconium-1,4-diphenyl-1,3-butadiene,
(dimethylsilyl-bis-2-methyl-4-phenylindenyl)zirconium(II) 1,4-diphenyl-1,3-butadiene, (dimethylsilyl-bis-tetrahydroindenyl)zirconium(II) 1,4-diphenyl-1,3-butadiene,
(dimethylsilyl-bis-tetrahydrofluorenyl)zirconiumdi(trimethylsilyl),
(isopropylidene)(cyclopentadienyl)(fluorenyl)zirconiumdibenzyl, and
(dimethylsilylpentamethylcyclopentadienylfluorenyl)zirconiumdimethyl.
Suitable polymerizable monomers include ethylenically unsaturated monomers, acetylenic compounds, conjugated or non-conjugated dienes, and polyenes. Preferred monomers include olefins, for examples alpha-olefins having from 2 to 20,000, preferably from 2 to 20, more preferably from 2 to 8 carbon atoms and combinations of two or more of such alpha-olefins. Particularly suitable alpha-olefins include, for example, ethylene, propylene, 1-butene, 1-pentene, 4-methylpentene-1,1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, or combinations thereof, as well as long chain vinyl terminated oligomeric or polymeric reaction products formed during the polymerization, and C10-30 xcex1-olefins specifically added to the reaction mixture in order to produce relatively long chain branches in the resulting polymers. Preferably, the alpha-olefins are ethylene, propene, 1-butene, 4-methyl-pentene-1, 1-hexene, 1-octene, and combinations of ethylene and/or propene with one or more of such other alpha-olefins. Other preferred monomers include styrene, halo- or alkyl substituted styrenes, tetrafluoroethylene, vinylcyclobutene, 1,4-hexadiene, dicyclopentadiene, ethylidene norbornene, and 1,7-octadiene. Mixtures of the above-mentioned monomers may also be employed.
In general, the polymerization may be accomplished at conditions well known in the prior art for solution phase, slurry, gas phase and high pressure Ziegler-Natta or Kaminsky-Sinn type polymerization reactions. Examples of such well known polymerization processes are depicted in WO 88/02009, U.S. Pat. Nos. 5,084,534, 5,405,922, 4,588,790, 5,032,652, 4,543,399, 4,564,647, 4,522,987, and elsewhere. Preferred polymerization temperatures are from 0-250xc2x0 C. Preferred polymerization pressures are from atmospheric to 3000 atmospheres. Molecular weight control agents can be used in combination with the present cocatalysts. Examples of such molecular weight control agents include hydrogen, silanes or other known chain transfer agents. The catalyst composition may be used by itself (homogeneously) or supported on an inert support such as silica, alumina or a polymer.
It is understood that the present invention is operable in the absence of any component which has not been specifically disclosed. The following examples are provided in order to further illustrate the invention and are not to be construed as limiting. Unless stated to the contrary, all parts and percentages are expressed on a weight basis. Where stated, the term xe2x80x9croom temperaturexe2x80x9d refers to a temperature from 20 to 25xc2x0 C., the term xe2x80x9covernightxe2x80x9d refers to a time from 12 to 18 hours, and the term xe2x80x9cmixed alkanesxe2x80x9d refers to a mixture of propylene oligomers sold by Exxon Chemicals Inc. under the trade designation Isopar(trademark) E.